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DNA Present (dna + present)
Selected AbstractsSulfate-reducing bacteria in marine sediment (Aarhus Bay, Denmark): abundance and diversity related to geochemical zonationENVIRONMENTAL MICROBIOLOGY, Issue 5 2009Julie Leloup Summary In order to better understand the main factors that influence the distribution of sulfate-reducing bacteria (SRB), their population size and their metabolic activity in high- and low-sulfate zones, we studied the SRB diversity in 3- to 5-m-deep sediment cores, which comprised the entire sulfate reduction zone and the upper methanogenic zone. By combining EMA (ethidium monoazide that can only enter damaged/dead cells and may also bind to free DNA) treatment with real-time PCR, we determined the distributions of total intact bacteria (16S rDNA genes) and intact SRB (dsrAB gene), their relative population sizes, and the proportion of dead cells or free DNA with depth. The abundance of SRB corresponded in average to 13% of the total bacterial community in the sulfate zone, 22% in the sulfate,methane transition zone and 8% in the methane zone. Compared with the total bacterial community, there were relatively less dead/damaged cells and free DNA present than among the SRB and this fraction did not change systematically with depth. By DGGE analysis, based on the amplification of the dsrA gene (400 bp), we found that the richness of SRB did not change with depth through the geochemical zones; but the clustering was related to the chemical zonation. A full-length clone library of the dsrAB gene (1900 bp) was constructed from four different depths (20, 110, 280 and 500 cm), and showed that the dsrAB genes in the near-surface sediment (20 cm) was mainly composed of sequences close to the Desulfobacteraceae, including marine complete and incomplete oxidizers such as Desulfosarcina, Desulfobacterium and Desulfococcus. The three other libraries were predominantly composed of Gram-positive SRB. [source] Quantification by real-time PCR of the magnitude and duration of leucocyte-associated viraemia in horses infected with neuropathogenic vs. non-neuropathogenic strains of EHV- 1EQUINE VETERINARY JOURNAL, Issue 3 2006G. P. Allen Summary Reasons for performing study: Neurological disease in horses caused by infection with certain ,paralytic' strains of equine herpesvirus-1 (EHV-1) is a potentially devastating condition the pathogenesis of which is poorly understood. Preliminary observations in both experimentally induced and naturally occurring cases of the central nervous system disease have revealed a more robust cell-associated viraemia in horses infected with paralytic isolates of EHV-1, relative to horses infected with abortigenic isolates. To investigate further this pathogenesis - rdevant question, the present study was performed using a greater number of horses and a more precise method for quantification of EHV-1 DNA present in viraemic leucocytes. Objective: To compare the magnitude and duration of leucocyte-associated viraemia in seronegative, age-matched foals following infection with paralytic vs. abortigenic isolates of EHV-1. Methods: Peripheral blood mononuclear cells (PBMC) were collected from 20 weanling foals at 2, 4, 7, 9, 11, 14 and 21 days after intranasal inoculation with either paralytic or abortigenic isolates of EHV-1. The amount of EHV-1 DNA present in each PBMC sample was measured by real-time quantitative PCR. Results: Foals inoculated with paralytic strains of EHV-1 developed both a greater magnitude and longer duration of PBMC-associated viraemia than foals inoculated with abortigenic strains of the virus. Conclusions: Both the higher magnitude and longer duration of cell-associated viraemia contribute to the risk for development of neurological signs in horses infected with paralytic strains of EHV-1. Potential relevance: Our results provide empirically derived, scientific data that contributes to a better understanding of the pathogenetic basis for the differing abilities of paralytic and abortigenic strains of EHV-1 to cause post infection central nervous system disease in the horse. The findings identify the importance of minimising the quantitative burden of viraemic leucocytes that follows exposure to the virus, by the use of effective therapeutic antiviral drugs and efficacious prophylactic vaccines that stimulate cytotoxic immune responses against EHV-1 infected cells. [source] Prevalence, quantification and typing of adenoviruses detected in river and treated drinking water in South AfricaJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2005J. van Heerden Abstract Aims:, Human adenoviruses (HAds), of which there are 51 serotypes, are associated with gastrointestinal, respiratory, urinary tract and eye infections. The importance of water in the transmission of HAds and the potential health risks constituted by HAds in these environments are widely recognized. Adenoviruses have not previously been quantified in river and treated drinking water samples. In this study, HAds in river water and treated drinking water sources in South Africa were detected, quantified and typed. Methods and Results:, Adenoviruses were recovered from the water samples using a glass wool adsorption-elution method followed by polyethylene glycol/NaCl precipitation for secondary concentration. The sensitivity and specificity of two nested PCR methods were compared for detection of HAds in the water samples. Over a 1-year period (June 2002 to July 2003), HAds were detected in 5·32% (10/188) of the treated drinking water and 22·22% (10/45) of river water samples using the conventional nested PCR method. The HAds detected in the water samples were quantified using a real-time PCR method. The original treated drinking water and river water samples had an estimate of less than one copy per litre of HAd DNA present. The hexon-PCR products used for typing HAds were directly sequenced or cloned into plasmids before sequencing. In treated drinking water samples, species D HAds predominated. In addition, adenovirus serotypes 2, 40 and 41 were each detected in three different treated drinking water samples. Most (70%) of the HAds detected in river water samples analysed were enteric HAds (serotypes 40 and 41). One HAd serotype 2 and two species D HAds were detected in the river water. Conclusions:, Adenoviruses detected in river and treated drinking water samples were successfully quantified and typed. The detection of HAds in drinking water supplies treated and disinfected by internationally recommended methods, and which conform to quality limits for indicator bacteria, warrants an investigation of the risk of infection constituted by these viruses. The risk of infection may have implications for the management of drinking water quality. Significance and Impact of the Study:, This study is unique as it is the first report on the quantification and typing of HAds in treated drinking water and river water. This baseline data is necessary for the meaningful assessment of the potential risk of infection constituted by these viruses. [source] Chemically modified tetracyclines stimulate matrix metalloproteinase-2 production by periodontal ligament cellsJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2006M. M. Bildt Background and Objective:, The purpose of this study was to investigate the effects of chemically modified tetracyclines (CMTs) on the production of gelatinases [matrix metalloproteinase (MMP)-2 and -9] by human periodontal ligament (PDL) cells, and on the activity of recombinant gelatinases. Material and Methods:, Human PDL cells were cultured with CMT-1, -3, -5, -7 or -8 in concentrations of 0, 1, 5, 10, 20, 50, 100, 200 and 500 µm. Gelatin zymography was used to determine MMP-2 and -9 production of the cells. The amount of DNA present in the cultures was analyzed using a fluorescent assay. The cytotoxicity of the CMTs was also determined. Recombinant human MMP-2 and -9 were incubated with the CMTs (0,500 µm) and their activity was analyzed using an internally quenched fluorogenic substrate. Results:, MMP-2 production was stimulated up to sevenfold by CMT-1, -3, -7 and -8 at low concentrations (10,200 µm). No significant amounts of MMP-9 were produced. In contrast, MMP-2 and -9 activity was reduced by ,,10,40-fold at higher concentrations (200,500 µm). CMT-5 had no effect on the production or on the activity of MMP-2 and -9. Only CMT-3 and -8 had cytotoxic effects on the PDL cells at the highest concentrations. Conclusion:, Surprisingly, CMTs are able to stimulate MMP-2 production at relatively low concentrations. However, at higher concentrations they exert a much stronger inhibitory effect on gelatinase activity. A possible stimulatory effect of CMTs on MMP production should be considered in their clinical use. [source] Positive ion electrospray ionization mass spectrometry of double-stranded DNA/drug complexesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2001Rajesh Gupta An Erratum has been published for this article in Rapid Communicatons in Mass Spectrometry 16(7) 2002,740,741. Positive ion electrospray ionization mass spectra of 16 base-pair double-stranded (ds)DNA have been obtained with essentially no ions from single-stranded DNA present. Single-stranded DNA was minimized by: (1) careful choice of DNA sequences; (2) the use of a relatively high salt concentration (0.1,M ammonium acetate, pH 8.5), and, (3) a low desolvation temperature (40,°C). Similarly, ESI-MS complexes of dsDNA with cisplatin, daunomycin and distamycin were obtained that contained only negligible amounts of single-stranded DNA. The complexes with daunomycin and distamycin were more stable to strand separation in the gas phase than dsDNA alone. This is in agreement with solution studies and with other recent gas phase results. These data contrast with many earlier ESI-MS studies of dsDNA and DNA/drug complexes in which ions from ssDNA are also normally observed. Copyright © 2001 John Wiley & Sons, Ltd. [source] Age Dependence of the Human Skeletal Muscle Stem Cell in Forming Muscle TissueARTIFICIAL ORGANS, Issue 3 2006Ralf Schäfer Abstract:, Human skeletal muscle stem cells from healthy donors aged 2,82 years (n = 13) and from three children suffering from Duchenne Muscular Dystrophy (DMD) were implanted into soleus muscles of immunoincompetent mice and were also expanded in vitro until senescence. Growth of implanted cells was quantified by structural features and by the amount of human DNA present in a muscle. Proliferative capacity in vitro and in vivo was inversely related to age of the donor. In vitro, a decline of about two mean population doublings (MPDs) per 10 years of donor's age was observed. Muscle stem cells from DMD children were prematurely aged. In general, cell preparations with low or decreasing content in desmin-positive cells produced more MPDs than age-matched high-desmin preparations and upon implantation more human DNA and more nonmyogenic than myogenic tissue. Thus, a "Desmin Factor" was derived which predicts "quality" of the human muscle tissue growing in vivo. This factor may serve as a prognostic tool. [source] | |||||||||||||